Mix coconut milk and pineapple preserves in a bowl with a stick blender. This breaks up pineapple pieces in the preserves into a finer texture so they are not so lumpy in the final dish. You can do this in the blender if necessary, or if you like chunky bits of pineapple just melt the preserves in the microwave for 30 seconds.
Mix in the cream of coconut. Cover the bowl and place in the refrigerator overnight.
Freeze the mixture in an ice-cream maker according to the manufacturer's instructions.
Once the mixture has finished churning, spoon into a container with a tight lid and put it in the freezer for at least an hour to harden before serving.